Brake fluid reservoir for a two-compartment master cylinder



United States Patent Inventor Juan Belart Walldort', Hessen, Germany Appl. No; 723,800 Filed April 24, i968 Patented Nov. 24, 1970 Assignee Alfred 'I'eves Gmbll Frankfurt am Main, Germany a corporation of Germany Priority May 2, 1967 Germany No. T33770 BRAKE FLUID RESERVOIR FOR A TWO- COMPARTMENT MASTER CYLINDER Primary ExaminerM. Cary Nelson Assistant Exam iner- Robert Jiller Attorney- Karl F Ross ABSTRACT: In order to prevent brake fluid from flowing locmmsannwing Figs from one chamber to the other of a two-chamber reservoir 11.8. CI. 137/255, when it is at a slant, this reservoir has a wall between its two 60/54.6 chambers that carries an equalizer with tubular mtercommu- Int. Cl F15b 7/08 meatmg arms extending into the upper portions of the side-by- Field olSeareh 137/255, side chambers and forming the sole passage for brake fluid 259, 262, 265, 576, 572, 57l; 303/85; 60/54.5X, therebetween. To and m refilllng, such an equalizer can have 54.6, 54.6E an open top located under a filler cap of the reservoir.

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; Pgtented Nov. 24, 1970 i F l JUAN BELART INVENTOR.

ATTORNEY 1 BRAKE rtuinnasa i'voin ron A wo- COMPAR'TMENT MASTER cvunnnn the brake-fluidlevel'therein.

Normallysuch two-chamber brake-fluid reservoirs have a dividing wall extendirigup'wardly' a certain distance between the chambers 'so' that brake fluid and air can only pa'sstrorn one chamber-to t ln=. other by flowing over this wall. These systems also are o ften equipped with a'n arrangement of floats connected to switches where the floats actuate the switches upon dropping below a predetermined level. The-switches in turn can set in operationan alarm forthedriver. V

The above-described arrangement has the disadvantage that its performance is onlysatisfactory when the vehicle is on the level or moving e'venlyjon level terrain. During ascent'or .descent of a slope or'a 'sudden' changeinspeed; the fluid spills from one chamber over the wall into theiother thereby causing the level in the one chamber to drop below the predetermined one. thus possibly'bringing the alarm into action. This is, of course, deceptive and dangerous forthedriver. 3

It is an object-of my invention to provide adevice capable of overcoming thisdisadvan tage while still fulfilling the function of a simple open space above the wall as air andfluid equalizer between the two chambers of a two-chamber brake-fluid reservoir for a dual-brake system. The device comprises an equalizer shaped likea cup blocking a passage in the dividing wall between the two chambers andprovided with two coaxial (preferably axially aligned) tubular arms whose free ends extend transversely from the wall into the upper portions of each chamber and whoseother endsterminate atand' communicate with one another through the equalizerbody. 'Inaddition'this device servesto'facilitatrefilling of the reservoir since it may be located under the filler capand maybe somewhat smaller than the ffillercap -o peningto ,allowdisplaced air 'to escape of the flller cap'new fluid is simply poured into jthecup and is substantially automatically, distributed to both chambers through the hollow arms. I

fluid reservoiraccording to my invention;

7 FIG. 2 is a detail ofFIGg 1, on anenlargedscale; and FIG. 3 is asec tion-takenalong line lIl.-II IofFlG.'2. FIG'. 1 shows a two charnberbrake-fluid reservoir 1 having chambers AandB connected by,"nipple s"'2, ,2 to a tandem and heldin place against the equalizer13 along a cup 21 in turn clamped on the cat 1'18 to which it is secured by ridge 27 and having holes 22' and 23 aligned with the confronting mouths of the tubular arms 14 and 15, respectively. The cap 18 has a boss18l into the circumferential groove 18" in which the ridge 27 is snap fitted. The cup 21 holds the screen 20 against an upwardly-concave seat 20' and returns'the equalizer against the upper edge-of the wall 12. If a sudden change in speed of the vehicleplaces the fluid in the reservoir! at the angle shown by dot-dash lines C inFIG. 1, the brake fluid is prevented from flowing from; chamber A to chamber 8 because the outside mouth of the arm 14 extends well into chamber A to a point where the angle of the brake fluid level relative to the reservoir 1 effects aless pronounced height change than it does closer tothe wall '12.The same is true if the fluid levelis slanted toward the front, back, or side walls of the chambers A, B. Of course, when the vehicle is onthe level ormoving evenly. the fluid or air can pass from one chamber AIB to the other through the two arms 14,15 and the equalizer' l3 with little hindrance if it reaches the level shown by dot-dash lineD in FIGS. 1 and 2,

Inorder'to refill the reservoir, one need only remove cap 18 and'pour the necessary-brake fluid intothe upstanding cylindrical portion'13-"'of the equalizer l3.'The fluid will automatically be'distributed between the two chambers A, B through the two ar ms 14, respectively. Air displaced by the fluid will be able to escape through gap 24 between the equalizer 13 and the mouth of the filler opening. Any impurities that pass into the equalizer 13 will be caught by screen and prevented from passing into the delicate brake mechanism;

' a ventilating valve. If, for some reason, one chamber A or B should be filled sooner than the other, on reaching level D shown by a dot-dash line in FIGS. 1 and 2, the fluid will be v around it when new .brake fluid is added. Thus, afteri'emoval.

master cylinder3 asshown-by dot dashlin'esfEach of the chambers A, B is associated 'witha level-actuated switch 6,7,

' only'one of whichis illustrated at-th'e left-handside of FIG. 1, This switch .is .o'perated'bya float 4 mounted on a rod 5 slidably mounted'in an electrically in'sulatingi block 9 held in I place on top of the chaniber A.-or by a cap 8 .(This rod 5 carries a conducting element 6 ;which cooperates withtwo contacts 7 to close asciricuit for'lighting an alarmdevice; the circuit-can'include a lampilO'fconnected to some vehicle power source such as a battery 11. t

As best seen in FIGS. Z a nd 3, a dividing wall 12 with a semicircular cutout 12 'at its top (see FIG, ,3) separates the I two chambers A, B. Directly above this cutout in the dividing wall 12 is a filler openingfin the form ofa neck 12" closed by a threaded filler cap 18 with an air vent 19. Clamped between this cap 18 and theu'pper edge '12" ofwall 12 is anequalizer .13

with tubular arms 14 and 15 and a plurality of bosses or radial protuberances 16 and 17 andrjbs'25, 27 on-the arms 14, 15 tolteep it centered in thefiller opening with a substantially annular gap 24 between it, and the filler openings mouth and clearances 25', 26 between the arms and the upper wall of the housing. In its interior is a cup-shaped screen 20 bonded to able to flow into the 'other chamber A or B.

With such a brake-fluid equalizing device, sudden changes inspe ed or the vehicle being ona slope will not generally cause'the brake fluid to flow from one chamber A or B of the reservoir. 1 into the'other;thereby creating an extremely low fluid level in one of the chambers-A or B and ultimately lighting the lamp 10. preferably the open ends 14' and 15' communicate with the chambers A and'B close to the centers between said indicators to introduce brakeefluid into said vessel; fluid distribution means communicating with said opening and having branches respectively communicating-with said chambers for leading brake fluid to both said chambers from said single filling opening; and. I means said fluid distribution 'means'for restricting of fluid "from one of said branches and'therespective one of said chambers into the other'of said chambers through the other of said branches.

2. A brake-fluid reservoir for a dual-brake system having a twocompartment master cylinder, said reservoir comprising a housing having a partition wall dividing the interior of said housing into two chambers having lower portions communicating with respective compartments of said cylinder and upper portions normally above a respective brake-fluid level therein, and an upright tubular central body forming a passage between said upper portions of said chambers, said passage opening into said chambers at locations offset from said wall, said upright tubula'r central body being disposed above said wall and having tubular arms extending transverse to said wall and communicating with one another through said body.

3. A reservoir as defined in claim 2 wherein said housing has a top wall spacedly overlying said partition wall and provided with a filler opening vertically aligned with the partition wall, said body having an upwardly open upper section received in said filler opening and closed lower section carrying said arms and resting on said partition wall.

4. A reservoir as defined in claim 3, further comprising a screen in said passage lining the interior of said body.

5. A reservoir as defined in claim 4, further comprising a cup having an open top end and a closed bottom end provided with at least one bore communicating with said tubular arms and shaped to hold said screen in said body.

6. A reservoir as defined in claim 5. further comprising a filler opening cap connected with said cup and provided with a vent hole allowing air passage therethrough.

7 A reservoir as defined in claim 3. further comprising spacer means on said arms engageable with said top wall.

8. A reservoir as defined in claim 3 wherein said filler opening is formed as a cylindrical neck on said top wall, further comprising space means on said upper section forming a clearance between said upper section and said neck.

9. A reservoir as definedin claim 3 wherein said partition wall is provided with an upwardly concave seat receiving said lower section and shaped complementarily thereto.

10. A reservoir as defined in claim 3 wherein said arms respectively communicate with said chambers at locations substantially at the centers thereof. 

